Description: Thermal Expansion Experiment Tool Kit Design to prove the effect of Thermal expansion and contraction Great physical teaching aids for teacher Material: Plastic and Metal Length: 16 cm/ 6.3 inch Color: Random Specification: 1. Let the steel ball pass through the ring several times to show that the steel ball can pass through the ring at normal temperature; 2. Heat the steel ball for 3-5 minutes, and then pass the steel ball through the ring. At this time, the steel ball expands due to heat, so it cannot pass through the ring; 3. Let the steel ball cool naturally, and the steel ball can pass through the ring Package Includes: 1 x Physical Teaching Aids(2 Pack) Note: Due to the manual measurement, please allow 1-2mm differences in size. Due to the light and screen difference, the item's color may be slightly different from the pictures. Please understand